399757945 has 4 divisors (see below), whose sum is σ = 479709540. Its totient is φ = 319806352.

The previous prime is 399757937. The next prime is 399757957. The reversal of 399757945 is 549757993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 549757993 = 5711 ⋅96263.

It can be written as a sum of positive squares in 2 ways, for example, as 58690921 + 341067024 = 7661^2 + 18468^2 .

It is a cyclic number.

It is not a de Polignac number, because 399757945 - 2³ = 399757937 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 399757945.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39975790 + ... + 39975799.

It is an arithmetic number, because the mean of its divisors is an integer number (119927385).

Almost surely, 2^399757945 is an apocalyptic number.

It is an amenable number.

399757945 is a deficient number, since it is larger than the sum of its proper divisors (79951595).

399757945 is an equidigital number, since it uses as much as digits as its factorization.

399757945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79951594.

The product of its digits is 10716300, while the sum is 58.

The square root of 399757945 is about 19993.9477092444. The cubic root of 399757945 is about 736.6576466981.

The spelling of 399757945 in words is "three hundred ninety-nine million, seven hundred fifty-seven thousand, nine hundred forty-five".